Sonochemical synthesis of hierarchical ZnO nanostructures

This work is about fabrication of ZnO nanostructures (ZnO-NS) via a simple sonochemical method. The chemicals used for the synthesis of various shaped ZnO are Zn salt, sodium hydroxide and ammonia solution without other structure directing agent or surfactant needed. This method is feasible and green, as it does not require high temperature and/or highly toxic chemicals. The shape of the ZnO-NS can be tuned by adjusting the ultrasound energy dissipated via varying the ultrasonication time from 5 to 60 min. It was found that uniform ZnO nanorods with diameter around 50 nm were formed after 15 min of ultrasonication while flowerlike ZnO-NS was formed after 30 min. This method produces high quality ZnO-NS with controllable shapes, uniformity, and purity.

► Four Solutions of zinc acetate and ammonia were prepared with same volume.
► High power ultrasound was applied to the solutions for 5, 15, 30, and 60 min.
► The prepared white powders were washed and centrifuged.
► The white precipitates were dried by oven at 60 °C.
► The structural, optical and morphological properties of prepared samples were investigated.